The aim of this project is the design and implementation of a system for analyzing the explainability of similarity between short texts (< 200 words), in Spanish language, with a special focus on the academic domain. For the system implementation, different models based on the BERT architecture will be used. A concise analysis of the explainability of the proposed system will be conducted, aiming to understand the intrinsic functioning of the method and to provide feedback to stakeholders, such as the author of the evaluated text or the professional deciding to use the system. Furthermore, based on the obtained results, an estimation of the system's goodness will be carried out through statistical analysis. This will enable both a comparison with other possible implementations and the proposal of future improvements that could have a positive impact on a more realistic assessment of texts.